With evolving eras, a new industrial manufacturing mode has transformed from mass production to flexible manufacturing in small amounts and diversity, hence requiring frequent changes in production lines and automated carrier systems with flexibilities. An automated Guided Vehicle (AGV) is an essential carrier in automated material transportation, and features advantages of occupying minimal space and production lines that can be flexibility adjusted. From the aspect of techniques, the object of positioning is accomplished by means of laser, magnetic columns and two-dimensional barcode tags. Among various techniques, laser map comparison and guiding method has an immense advantage. The positioning calculation of the laser map comparison and guiding method can be divided into two parts: calculation of global positioning in an entire environment, and calculation of fine positioning by using landmark features. Currently, only the contour of the landmark is used for positioning calculation. However, because the signal of a laser scanner includes noise and the noise is also generated when laser reaches edges of the landmark, achieving positioning having position accuracy under a millimeter scale can be quite challenging.